Pen needle assembly

ABSTRACT

A pen needle, comprising a reusable adapter configured for attachment to a distal end of a medication pen, the adapter having a proximal needle for accessing the interior of the pen injector and a fitting on the distal side for mating with a patient end needle assembly, and a disposable patient-end needle assembly having a base configured for mating with the fitting on the distal side of the adapter and a patient-end needle extending from a distal end of the base.

This application is a division of U.S. patent application Ser. No.14/655,710, filed Jun. 25, 2015, U.S. Pat. No. 10,350,371, which is theU.S. National Stage of International Patent Application No.PCT/US2013/076787, filed on Dec. 20, 2013, which claims the benefitunder 35 U.S.C. § 119(e) of U.S. Provisional Application No. 61/746,108,filed Dec. 26, 2012, U.S. Provisional Application No. 61/746,109, filedDec. 26, 2012, and U.S. Provisional Application No. 61/746,103, filedDec. 26, 2012, all of which are herein incorporated by reference.

BACKGROUND OF THE INVENTION Field of the Invention

The invention is directed to a pen needle which may be installed on adrug delivery device, such as a medication pen, including modificationsthat make the pen needle more cost effective and user friendly.

Description of the Related Art

Pen needles are widely used in medication delivery systems forself-administered injectable drugs. The pen needles that are commonlyused have a single stainless steel cannula extending through theneedle-bearing hub. The non-patient end of the needle pierces theclosure of the drug storage compartment of the medication pen while thepatient end of the needle is adapted for insertion into the patient'stissue. Thus, in the conventional pen needle, since a single cannula isused, both ends of the cannula have the same inner and outer diameter. Aproblem exists in that thinner gauge needles which may be preferred forpatient comfort do not reliably pierce the septum of the medicationcompartment when the pen needle is installed on the medication pen.

Another drawback of the commonly available pen needles is that they donot provide the user with an indication that the needle has reached theoptimal penetration depth. The user relies on subjective sensation ofpain when performing an injection to determine the depth of penetration,which may result in too much or too little penetration. An injectionthat is too deep may cause unnecessary pain when the needle is pressedtoo hard against the body, while an injection that is not deep enoughmay result in improper dosing. Thus, there is a need for pen needlesthat provide penetration depth indication.

These and other drawbacks of the prior art are achieved according to thepresent invention as described in the following specification andclaims.

SUMMARY OF THE INVENTION

The inventors herein have explored ways to make lower cost pen needleswith reduced materials usage while retaining the popular functionalfeatures of current products. In one aspect, the disclosure pertains toa pen needle which has a plastic non-patient end cannula which may bemolded in one piece with the hub. This affords the advantage that alarger diameter cannula may be used on the non-patient end to providestrength to pierce the septum of the medication cartridge, while alighter gauge stainless steel needle is used on the patient end forincreased patient comfort during an injection.

In another aspect, the invention is directed to a pen needle having aneedle-bearing hub with a two part construction, including an adapterwhich is attached to the medication delivery device for repeated use,and a single use needle. The volume of disposable needle components issignificantly reduced compared to a conventional pen needle in which theentire hub is disposable.

In still another aspect, the disclosure pertains to a pen needle whichprovides an audible, tactile, and/or visual indication of penetrationdepth so that the user knows when full injection penetration depth hasbeen achieved. The penetration depth indication is provided by a movableshield that may be incorporated with the above described hub designswith a plastic non-patient end cannula and/or two-piece hub.

Thus, in one aspect the invention is a disposable pen needle,comprising: a hub adapted for attachment to an injection pen body havinga plastic non-patient end needle, and a metal patient end cannulaattached to the hub.

In embodiments, the patient end cannula according to the invention is 33gauge or smaller and the non-patient end needle is larger gauge that thepatient end needle. However, the invention is not limited to a 33 gaugepatient end needle.

In another aspect, the pen needle according to the invention comprises ahub which is split in two, comprising: a reusable adapter configured forattachment to a distal end of a medication pen, having a proximal needlefor accessing the interior of the pen and a fitting on the distal sidefor mating with a patient end needle assembly. The disposablepatient-end needle assembly has a base configured for mating with thefitting on the distal side of the adapter and a patient-end needleextending from a distal end of the base.

In embodiments according to this aspect of the invention, the pen needlefurther comprises a cover on the needle assembly, mating with the baseand forming a sterile enclosure around the needle prior to use andforming a disposal-safe assembly after use.

In other embodiments according to this aspect of the invention, theadapter is provided with a valve or septum to prevent fluid leakage fromthe interior of the medication pen when the needle assembly is removed.Alternatively, a separate cap may be provided for the adapter to coverthe orifice on the distal end of the adapter when the needle assembly isnot present.

In still another aspect, the invention is a pen needle that providesaudible and/or tactile indication of penetration depth. In embodiments,the pen needle comprises a needle-bearing hub adapted for attachment toa medication pen body, having a central post extending distally from amain body portion of the hub. The main body portion of the hub is widerthan the post. The post is provided with a radially outwardly projectingmember and at least one recess adjacent the main body portion of thehub. A cup (sometimes referred to as the “shield”) is radially situatedaround the post and has a hole to allow passage of the needle. The cuphas a skin contact surface on a distal side thereof and a sidewallextending proximally from the skin contact surface. The sidewall has aninwardly projecting member engaging the outwardly projecting member onthe post. The cup is movable from a first position, in which theinwardly projecting member is on a distal side of the outwardlyprojecting member on the post, and a second position, in which theinwardly projecting member on the cup engages a recess adjacent the mainbody portion of the hub. Movement of the cup from the first position tothe second position creates an audible and/or tactile indication fromthe engagement of the inwardly projecting member on the cup and therecess adjacent the main body portion of the hub to indicate fullpenetration depth of the needle. An optimal patient end needle length ispredetermined for the intended use of the medication pen.

In embodiments, a central post is not provided on the hub and the cup isreceived over the widest portion of the hub. In this case, an outwardlyprojecting member may be provided on a radially outward surface on theside of the widest portion of the hub to engage an inwardly projectingmember on the cup.

In still another aspect, a pen needle according to the inventionprovides a visual indication that optimal penetration depth has beenachieved. In this aspect, the cup is provided with at least one window,and a color indicator is provided on the hub which is not visiblethrough the window in the first position, but is visible through thewindow in the second position, so that a user knows that a predeterminedinjection depth has been achieved.

Visual indication may be combined with audible/tactile indication, andpenetration depth indication in general may be combined with the plasticnon-patient end needle and the two-piece hub embodiments describedabove.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional view of a pen needle having a plastic nonpatient end needle according to an embodiment of the invention.

FIG. 2 is an isometric view of a pen needle according to the embodimentof FIG. 1.

FIG. 3 is an isometric view of the pen needle according to theembodiment of FIG. 1 showing the non-patient cannula.

FIG. 4 is an exploded view of a needle-bearing hub with an audibleand/or tactile penetration depth indication cup according to anotherembodiment of the invention.

FIG. 5 is a view of the assembly of FIG. 4 with the cup installed on thehub.

FIG. 6 is a side view of the assembly of FIG. 5 in a state prior toreaching full penetration depth.

FIG. 7 is a cross sectional side view of the assembly of FIG. 5 prior toreaching full penetration depth.

FIG. 8 is a cross sectional side view of the assembly of FIG. 6 at fullpenetration depth.

FIG. 9 is a perspective view of the inside of a cup according to oneembodiment of the invention.

FIG. 10 depicts the needle assembly component of a two-piece hubaccording to another embodiment of the invention.

FIG. 11 depicts the adapter component of the two-piece hub with anadapter cover.

FIG. 12 depicts a two-piece hub assembly.

FIG. 13 is an exploded view of the two-piece hub assembly. Including theadapter, single use needle, and cover.

DETAILED DESCRIPTION OF THE INVENTION

As used herein, the “distal” direction is in the direction of theinjection site, and the “proximal” direction is the opposite direction.The “axial” direction is along, or parallel to, the longitudinal axis ofthe syringe body. The cannula is generally arranged axially in amedication pen. “Radially” is a direction perpendicular to the axialdirection. Thus, “radially inward” generally means closer to the needle.The accompanying figures are schematic and not to scale.

FIG. 1 is a cross section of a disposable pen needle 10 with a plasticnon-patient end cannula 30. The plastic non-patient end cannula 30 maybe molded as part of the hub 40, which is adapted for attachment to amedication pen, or the like, via threads 42 or other attachment meansknown in the art, such as cooperating detents and protrusions which snaptogether. The patient-end of the needle is a stainless steel cannula 20with a single point (similar to a syringe needle) which can be attachedto the hub 40 with an adhesive, such as a UV curable adhesive, spinwelding or insert molding. Alternatively, the needle can be attached tothe hub with a mechanical lock or other means known in the art.

Because the non-patient end cannula does not pierce the patient'stissue, it may be made with a larger inside and outside diameter, whichmakes the element stronger and more reliable for insertion into themedication compartment of a medication delivery device such as amedication pen where the non-patient end cannula pierces a septum of amedication cartridge. The non-patient end needle is not required to bethe same gauge as the patient-end needle, and in fact the non-patientend of the needle is preferably larger than the patient end. Thus, amore stable piercing mechanism is provided. In embodiments, the patientend cannula is 33 gauge or smaller and the non-patient end needle islarger gauge.

The non-patient end needle, even if made of a lower modulus material,such as plastic, can be made sufficiently strong by increasing theoutside diameter. An exemplary calculation of the inside and outsidediameter based on the maximum buckling load for a preferredpolypropylene plastic material is shown below. Such calculation is notto be deemed as limiting the invention:

Elements Unit Formula Calculations Max Buckling Load F (lb) Fmax = π²EI/(KL)² 1.501039677 Constant K 2 2 Moment of Inertia I (in⁴) I =π(Dout⁴ − Din⁴)/64 1.161528E−07 Cross Sectional Area A (in²) A = π(Dout²− Din²)/4 0.000883573 Max Axial Stress

 (psi)

 = Fmax/A 1698.8294 Modulus of Elasticity/Youngs E (psi) 213333 213333Modulus Length of Column L (in) 0.238 0.238 Diameter NP Cannula Dia(inches) Din 0.03 0.03 Dout 0.045 0.045 Constant Pi (π) 3.1415926543.141592654

The inner diameter of a non-patient end cannula according to theinvention is preferably in a range of 0.002 to 0.100 inches. The outerdiameter of the non-patient end plastic cannula is preferably in a rangeof 0.007 to 0.1000 inches. The patient end needle is preferablystainless steel with a sharpened bevel. The patient end needle may be,for example, 30 gauge, 31 gauge, 32 gauge, 33 gauge or even smaller. Inthe most preferred embodiment the patient end needle is insert moldedwith the non-patient end cannula.

When used with a medication pen, since a portion of the flow is througha larger diameter, the flow of medication can be increased, permittinglower thumb-button force and enabling the use of a small cannula for theinjection end cannula.

FIG. 2 depicts the outside of a hub 40 according to the invention. Incontrast to a conventional pen needle, where a protruding adhesive wellis provided so that the cannula can be retained in a tubular structureon the hub, the patient-end needle according to the embodiment shown isreceived inside the non-patient end plastic cannula which may be insertmolded directly with the hub, and is not required to be mounted on aprotruding member. This permits the side 44 of the hub that is facingthe patient to be flat and unobstructed during an injection.

FIG. 3 depicts the non-patient cannula, which in some embodiments ismolded in one piece with the hub. As with the currently availabledesigns, the non-patient end cannula preferably does not protrude beyondthe plane formed by the edge surrounding the open proximal end of thehub 40.

FIG. 4 is an exploded view of an assembly 400 according to anotherembodiment of the invention, in which the pen needle provides an audibleand/or tactile indication that injection depth has been achieved. Inthis view, hub 40 is provided with a central post 42 extending distallyfrom the main body portion of the hub 40. In the embodiment shown,needle 20 is installed in an adhesive well 48 which protrudes from thehub radially inward of the post 42. The needle 20 is fixed in an axialposition. It is not necessary to provide a gap between post 42 andadhesive well 48, and these can be formed with a flat patient-facingsurface.

In the embodiment shown, post 42 is provided with a pair of radiallyprojecting members 32, 34 forming parallel rings around the post 42.Each ring may be provided with an inclined surface sloping radially awayfrom the patient end of the needle to facilitate the engagement of a cup50 over the post 42 as described below. Projection 34 defines a recess36 on the proximal side of the projection 34 and adjacent the wider mainbody portion of the hub 40.

FIG. 5 depicts the cup received on the post. Needle 20 projects throughhole 52 in the cup 50. The position of cup 50 shown in FIG. 5 is thefurthest proximal position that can be achieved by the cup 50 withrespect to the hub 40. This is the position reached at full injectiondepth, when the skin-contacting surface 56 contacts the patient's skinand the needle is at an optimal injection depth. An optimal patient endneedle length is predetermined for the intended use of the medicationdelivery device, typically in the case of medication pen, an intradermalor subcutaneous injection.

The cup 50 has a sidewall extending in a proximal direction away fromthe skin contact surface 56. The sidewall is received around post 42. Asshown in the cross sectional view of FIG. 7, an inwardly projectingmember 58 on the proximal end of the sidewall of the cup engages thedistal end of the projection 34 in a first position, shown in FIG. 7 andengages a recess 36 on the proximal side of the projection in a secondposition, as shown in FIG. 8. In a preferred embodiment, the inwardlyprojecting member forms a ring around the interior surface of cup 50.Other embodiments of the radially inward and outward members on the postand cup are within the scope of the invention. For example, a spiralchannel may be provided on the hub, and a projection on the cup followsa helical path formed by the thread-like channel on the hub while theskin-contact surface 56 is pushed proximally. When the optimalpenetration depth is achieved, a projection on the cup engages a recessin the hub like a hook. Other mechanisms known in the art may be used toprovide an audible and/or tactile sensation when the cup is movedproximally. For example, one or more slots provided on the outside ofthe hub engaging with one or more protrusions on an interior surface ofthe cup would be an acceptable equivalent for the rings described above.

Preferably, the cup engages the hub so that the cup is not easilyremoved prior to injection, and prevented from movement in a distaldirection after full injection depth is reached. In the position of FIG.7, for example, prior to an injection, the cup 50 may be retainedbetween projections 32 and 34 with an interference fit. Movement fromthe position of FIG. 7 to the position of FIG. 8 is accompanied by anaudible and/or tactile indication as the inwardly projecting member 58is received in recess 36. As the patient inserts the needle the tissuecomes into contact with the skin-contacting surface 56 and forces itdownward. This forces the cup to slide down the central post over thering-shaped projection. The outwardly projecting member 34 on the postand the inwardly projecting member on the cup are sized so that acertain amount of force is required to overcome the resistance.Generally at least about 2 psi, and preferably above about 5 psipressure must be applied to overcome the resistance to proximal movementof the cup. Creating an audible snap from this engagement requires acertain amount of elasticity in the cap, as understood by the person ofordinary skill in the art.

According to embodiments of the invention, the device provides a visualindication that full penetration depth has been achieved and that thepen needle has been used. As shown in FIG. 6, windows 54 are providedaround the circumference of the cup toward the distal end. A colorindicator band on the hub post which is not visible through the windowsin the first position becomes visible in the second position.Conventional pen needles do not provide an indication that the penneedle has been used. The system according to the invention is expectedto improve user compliance.

FIGS. 10 through 13 depict another embodiment according to theinvention, wherein the conventional hub is replaced with a two-pieceassembly. According to this embodiment of the invention, as shown inFIG. 10, disposable patient end needle assembly 100 is provided with acap 110 which mates with base 26 to provide a sterile enclosure aroundthe needle. The disposable pen needle assembly may be provided with apeelable sterile label, similar to the “teardrop label” provided with adisposable pen needle hub according to current and conventionaldesign—except that the inventive needle assembly is smaller.Alternatively, a plastic lid over the end of the cap 110 may be used.

FIG. 11 and FIG. 13 depict adapter body 120 of an adapter 111 which isprovided with threads 70 or other means for connecting to a medicationdelivery device such as a medication pen. The adapter 111 includes aproximal, non-patient end needle 112 for accessing the interior of themedication pen. In embodiments, non-patient end cannula 112 is plasticand may be molded in one piece with the adapter 111 as described above,reducing the number of beveled stainless steel parts required for theassembly. Attaching the adapter 111 to the medication pen pierces theseptum of a medication pen cartridge. The distal or patient side of theadapter 111 includes a fitting 128 for mating with the needle assembly.In embodiments, the reusable adapter 111 is intended to remain on themedication pen for 10 to 30 uses, mirroring the usage pattern of themedication pen cartridge. Thus, the adapter 111 and the needle assemblymay be packaged and sold separately if desired.

In embodiments, fitting 128 is provided with a custom taper surroundingorifice 134 of the adapter 111, providing fluid connection between theadapter 111 and the needle assembly 110. This arrangement is similar inprinciple to a miniature luer lock fitting on a syringe. The needleassembly may be provided with locking protrusions 126 to mate with theadapter fitting 128, for example. The orifice 134 may be provided withan adapter cap 140 which is installed after the needle is removed toprevent leakage. Alternatively, a valve or septum may be incorporatedinto the adapter to prevent leakage.

A primary advantage of the pen needle assembly according to theinvention is the reduction in size of the disposable component. Acommercial pen needle currently marketed has an outer volume on theorder of 0.15 in³. The disposable needle assembly will reduce thisvolume by at least one third, preferably by one half, and mostpreferably by two thirds. Thus, in the presently preferred embodiments,the volume of a needle assembly and cap according to the invention isexpected to be as low as 0.10 in³ and even as low as 0.05 in³. The costsavings of using the two-part hub are realized in reduced packaging andreduced materials costs. Additionally, the consumer disposes of only thepatient end needle when finished with an injection, reducing the amountof sharps to be disposed of.

In all of the foregoing embodiments, the parts of the pen needleaccording to the invention are preferably injection molded plasticexcept for the patient end needle. The parts described in the abovetwo-part hub can be fabricated with less than 75 percent and preferablyabout 50 percent less volume of plastic than a current pen needledesign.

The above description of the preferred embodiments is not to be deemedlimiting of the invention, which is defined by the following claims. Theforegoing description should provide the artisan of ordinary skill withsufficient information to practice variants of the embodimentsdescribed. Features described in connection with one embodiment orindependent claim may be used in connection with another disclosedembodiment or another independent claim without departing from the scopeof the invention.

What is claimed is:
 1. A pen needle, comprising: a reusable adapterconfigured for attachment to a distal end of a medication pen, theadapter having a proximal adapter needle for establishing fluidcommunication with an interior of the medication pen and a fitting on adistal side for mating with a disposable patient end needle assembly;wherein the disposable patient-end needle assembly includes a baseconfigured for mating with the fitting on the distal side of the adapterand a patient-end needle extending from a distal end of the base; andthe adapter includes a valve or septum to prevent fluid leakage from theinterior of the medication pen.
 2. The pen needle according to claim 1,further comprising a cover on the disposable patient-end needleassembly, mating with the base and forming a sterile enclosure aroundthe patient-end needle prior to use.
 3. The pen needle according toclaim 2, wherein the disposable patient-end needle assembly furtherincludes a peelable label as part of the sterile enclosure around thepatient-end needle prior to use.
 4. The pen needle according to claim 1,wherein the fitting on the adapter is tapered and the disposablepatient-end needle assembly engages and locks onto the tapered fittingfor a leak-free engagement of the disposable patient-end needle assemblyand the adapter.
 5. The pen needle according to claim 4, wherein thedisposable patient-end needle assembly includes a portion correspondingto the taper on the fitting of the adapter.
 6. The pen needle accordingto claim 1, wherein the fitting surrounds an orifice of the adapter. 7.The pen needle according to claim 1, wherein the adapter is providedwith a cap to cover an orifice on the distal side of the adapter whenthe disposable patient-end needle assembly is not present.
 8. The penneedle according to claim 1, wherein the adapter needle comprises aplastic non-patient end needle integrally molded with a hub of theadapter.
 9. The pen needle according to claim 1, wherein the fitting ofthe adapter is configured to mate with locking protrusions of thedisposable patient-end needle assembly.
 10. The pen needle according toclaim 9, wherein the locking protrusions locks a distal end of thefitting located on an inside of the adapter so that a correspondingportion engages the fitting for a leak-free engagement of the disposablepatient-end needle assembly and the adapter.